The present invention relates to circuits for pulses, and, more particularly, to generating electrical pulses of amplitudes greater than that of the electrical energy supply especially for forming current pulses for sonic waveguides.
Electrical pulses, that is, substantial changes in amplitude level of an electrical variable over a relatively short time, are needed to operate various electrical devices and perform various electrical functions. One such device is a sonic waveguide based relative translation distance measuring system, or instrument. In such systems, an electrical current pulse is applied through an electrical conductor wire encased in a ferromagnetic material waveguide tube or, alternatively, through a ferromagnetic material electrical conductor rod that also serves as the sonic waveguide. An external magnet, serving as a position marker by being guided along the tube to have a position therealong that is dependent on the distance to be measured, provides a magnetic field which interacts with the translating magnetic field established by the current pulse is applied through the wire or rod. That interaction results in a torque in the waveguide, whether tube or conductor, at the location of the interaction to thus provide a torsion pulse at that location in the sonic waveguide that is transmitted along that waveguide including back toward the source of the current pulse. The time duration between the imitiation of the current pulse and the receiving of the sonic pulse reaching a sensing location at the sensing end of the waveguide is a measure of the distance to the variable position magnet from that location.
Such current pulses in the wire or guide in the relative translation distance measurement system are repeated frequently to provide a continual update of the position of the marker magnet, and so the distance thereto. The current pulse must be of sufficient magnitude to generate the necessary magnetic field for interacting with the magnetic field of the varying position marker magnet, but not excessive which would waste energy. In some situations, control of the pulse duration is also desired. Often, a voltage must be temporarily provided between the wire and the sonic waveguide tube or conductor rod to form the current pulse in the wire or rod which is larger than that available from the voltage supply locally available to the current pulsing circuit, although in some situations that voltage may be less than what is locally available. Thus, there is a desire for a current pulsing circuit which can provide a substantial electrical current pulse on a pulse carrying wire of a desired duration despite limits on the voltage supply available to the circuit, and which can provide such pulses at a suitable frequency.